This invention concerns LED lighting devices, and is directed particularly to an efficient assembly of an LED array and a heat sink, which can also include LED electronics.
Newer, more powerful LED arrays, instead of being surface mounted as individual LEDs on a PCB, are constructed as a larger tight array of LEDs. Also they can be “grown” on a single silicon chip and clustered together on a wafer. These are called chip-on-board or COB. There can be many dozens of individual LEDs in an array or cluster. Alternatively, newer LEDs such as the Cree XD 16 individual diodes are designed to allow building of tight clusters of LEDs that can potentially mix a range of wavelengths in a tight cluster of the same or similar size to the COB arrays. These arrays are mounted on a heat conducting substrate ranging from aluminum to copper or ceramic. The entire back surface of the mounted array needs to maintain strong thermal contact with a heat sink for cooling of LEDs in order to maximize light output. Manufacturers sell a wide range of carriers designed to make electrical contact with the LED array and maintain force to hold the array against a heat sink. These holders or carriers are expensive and take up space in the device. A typical assembly would have a holder, a heat sink and a separate driver that powers the LED. As an example, see U.S. Pat. No. 9,746,170, owned by the assignee of this invention.
To minimize costs as well as to make the design small and compact for a lightweight product, it would be desirable to remove the typical holder and efficiently fix the LED array in place while making tight thermal contact within the heat sink and secure electrical connection for the LED array. In addition it would be advantageous to integrate the holding function into the driver PCB.